[llvm] r253459 - Revert "Revert "Strip metadata when speculatively hoisting instructions (r252604)"
Igor Laevsky via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 18 06:50:19 PST 2015
Author: igor.laevsky
Date: Wed Nov 18 08:50:18 2015
New Revision: 253459
URL: http://llvm.org/viewvc/llvm-project?rev=253459&view=rev
Log:
Revert "Revert "Strip metadata when speculatively hoisting instructions (r252604)"
Failing clang test is now fixed by the r253458.
Modified:
llvm/trunk/lib/Analysis/LoopInfo.cpp
llvm/trunk/lib/Transforms/Scalar/LICM.cpp
llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll
llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll
llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll
Modified: llvm/trunk/lib/Analysis/LoopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopInfo.cpp?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopInfo.cpp Wed Nov 18 08:50:18 2015
@@ -120,6 +120,13 @@ bool Loop::makeLoopInvariant(Instruction
// Hoist.
I->moveBefore(InsertPt);
+
+ // There is possibility of hoisting this instruction above some arbitrary
+ // condition. Any metadata defined on it can be control dependent on this
+ // condition. Conservatively strip it here so that we don't give any wrong
+ // information to the optimizer.
+ I->dropUnknownNonDebugMetadata();
+
Changed = true;
return true;
}
Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Wed Nov 18 08:50:18 2015
@@ -672,6 +672,10 @@ static bool hoist(Instruction &I, BasicB
// Move the new node to the Preheader, before its terminator.
I.moveBefore(Preheader->getTerminator());
+ // Metadata can be dependent on the condition we are hoisting above.
+ // Conservatively strip all metadata on the instruction.
+ I.dropUnknownNonDebugMetadata();
+
if (isa<LoadInst>(I)) ++NumMovedLoads;
else if (isa<CallInst>(I)) ++NumMovedCalls;
++NumHoisted;
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Nov 18 08:50:18 2015
@@ -1618,6 +1618,11 @@ static bool SpeculativelyExecuteBB(Branc
SpeculatedStore->setOperand(0, S);
}
+ // Metadata can be dependent on the condition we are hoisting above.
+ // Conservatively strip all metadata on the instruction.
+ for (auto &I: *ThenBB)
+ I.dropUnknownNonDebugMetadata();
+
// Hoist the instructions.
BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(),
ThenBB->begin(), std::prev(ThenBB->end()));
Modified: llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll (original)
+++ llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/licm.ll Wed Nov 18 08:50:18 2015
@@ -5,7 +5,7 @@
; CHECK: @foo
; CHECK: entry:
-; CHECK-NEXT: %tmp3 = load double*, double** @P, !tbaa !0
+; CHECK-NEXT: %tmp3 = load double*, double** @P
; CHECK-NEXT: br label %for.body
@P = common global double* null
Modified: llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll (original)
+++ llvm/trunk/test/Transforms/LICM/hoist-deref-load.ll Wed Nov 18 08:50:18 2015
@@ -388,5 +388,49 @@ for.end:
ret void
}
+; In this test we should be able to only hoist load from %cptr. We can't hoist
+; load from %c because it's dereferenceability can depend on %cmp1 condition.
+; By moving it out of the loop we break this dependency and can not rely
+; on the dereferenceability anymore.
+; In other words this test checks that we strip dereferenceability metadata
+; after hoisting an instruction.
+
+; CHECK-LABEL: @test10
+; CHECK: %c = load i32*, i32** %cptr
+; CHECK-NOT: dereferenceable
+; CHECK: if.then:
+; CHECK: load i32, i32* %c, align 4
+
+define void @test10(i32* noalias %a, i32* %b, i32** dereferenceable(8) %cptr, i32 %n) #0 {
+entry:
+ %cmp11 = icmp sgt i32 %n, 0
+ br i1 %cmp11, label %for.body, label %for.end
+
+for.body: ; preds = %entry, %for.inc
+ %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
+ %arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
+ %0 = load i32, i32* %arrayidx, align 4
+ %cmp1 = icmp sgt i32 %0, 0
+ br i1 %cmp1, label %if.then, label %for.inc
+
+if.then: ; preds = %for.body
+ %c = load i32*, i32** %cptr, !dereferenceable !0
+ %1 = load i32, i32* %c, align 4
+ %arrayidx3 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
+ %2 = load i32, i32* %arrayidx3, align 4
+ %mul = mul nsw i32 %2, %1
+ store i32 %mul, i32* %arrayidx, align 4
+ br label %for.inc
+
+for.inc: ; preds = %for.body, %if.then
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, %n
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.inc, %entry
+ ret void
+}
+
attributes #0 = { nounwind uwtable }
!0 = !{i64 4}
Modified: llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll?rev=253459&r1=253458&r2=253459&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll (original)
+++ llvm/trunk/test/Transforms/SimplifyCFG/SpeculativeExec.ll Wed Nov 18 08:50:18 2015
@@ -69,3 +69,29 @@ end:
ret i8* %x10
}
+
+define i32* @test5(i32 %a, i32 %b, i32 %c, i32* dereferenceable(10) %ptr1,
+ i32* dereferenceable(10) %ptr2, i32** dereferenceable(10) %ptr3) nounwind {
+; CHECK-LABEL: @test5(
+entry:
+ %tmp1 = icmp eq i32 %b, 0
+ br i1 %tmp1, label %bb1, label %bb3
+
+bb1: ; preds = %entry
+ %tmp2 = icmp sgt i32 %c, 1
+ br i1 %tmp2, label %bb2, label %bb3
+; CHECK: bb1:
+; CHECK-NEXT: icmp sgt i32 %c, 1
+; CHECK-NEXT: load i32*, i32** %ptr3
+; CHECK-NOT: dereferenceable
+; CHECK-NEXT: select i1 %tmp2, i32* %tmp3, i32* %ptr2
+; CHECK-NEXT: ret i32* %tmp3.ptr2
+
+bb2: ; preds = bb1
+ %tmp3 = load i32*, i32** %ptr3, !dereferenceable !{i64 10}
+ br label %bb3
+
+bb3: ; preds = %bb2, %entry
+ %tmp4 = phi i32* [ %ptr1, %entry ], [ %ptr2, %bb1 ], [ %tmp3, %bb2 ]
+ ret i32* %tmp4
+}
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